A simple and available method for identification and authentication of edible vegetable oils using a smartphone and chemometric analysis is presented. Identification of oils by the region of origin and species (olive, sunflower, rapeseed, cotton, etc.), as well as their authentication (authenticity and falsification) were carried out by the intrinsic color of vegetable oils and fluorescence under irradiation of the samples with monochromatic ultraviolet light (A = 365 nm). The iPhone X and iPhone XIII smartphones (Apple, USA) equipped with a specialized software (RGBer) were used as a color-recording device in the study of optical and colorimetric characteristics. A smartphone-based test device and a method for measuring colorimetric parameters in an additive RGB system for identification and authentication of edible vegetable oils are proposed. The processing of the data array (for three variables R, G, and B) was carried out using the XLSTAT software product. To differentiate the samples by the region of origin and species, the method of principal components and hierarchical cluster analysis were used. Approbation of the developed approach was carried out on the samples of commercially produced vegetable oils purchased in retail stores. The use of algorithms of chemometric analysis made it possible to establish the authenticity of vegetable oils, identify them by the region of origin, and to reveal facts of falsification by diluting expensive oils with cheaper ones. The developed method for assessing the quality of plant products is advantageous for the simplicity of hardware design, the availability of technical means and materials used, the possibility of in situ analysis without involving highly qualified specialists, and the clarity and speed of obtaining information.

Glyphosate and glufosinate are broad-range, non-selective herbicides that contaminate plant products used in fattening farm animals which in turn bears the risks of contamination of the whole food chain. The goal of this study is to develop a selective procedure for the chromato-mass spectrometric determination of glyphosate, aminomethylphosphonic acid (glyphosate metabolite) and glufosinate in meat, offal and milk. The limit of quantitative determination of glyphosate and glufosinate in meat and offal is 0.05 mg/kg, aminomethylphosphonic acid is 0.4 mg/kg; the limit of quantitative determination of glyphosate and glufosinate in milk is 0.02 mg/kg, aminomethylphosphonic acid is 0.05 mg/kg. The compounds to be determined are extracted from the objects under study with a solution of sulfbsalicylic acid, the primary purification of the extracts is carried out using a reverse-phase C18 sorbent, the compounds to be determined are derivatized using 9-fluorenylmethoxycarbonyl chloride, and the final purification of the derivatives is carried out on a sorbent exhibiting weak cation exchange properties. The purified extract is concentrated, diluted with a mixture of methanol and acetic acid in water, centrifuged and then used for analysis. Chromatographic separation is performed on a column with a reversed-phase C18 sorbent. Tandem mass-spectrometry is used for detection of the compounds under study. The calibration dependences for the determined compounds are linear, the correlation coefficient (K) > 0.99. The validation of the procedure showed that the relative expanded uncertainty in the lower range of the determined contents ranged from 27 to 41% for glyphosate, from 25 to 29% for aminomethylphosphonic acid, and from 25 to 34% for glufbsinate, depending on the type of object of analysis. The obtained values of the limit of quantitative determination are consistent with the temporary maximum allowable levels set in SanPiN 1.2.3685-21.

The results of studying the effect of alcohol additives (ethanol and isopropanol) on the analytical signals of 15 elements in their determination by the method of inductively coupled plasma-mass spectrometry (ICP-MS) are presented. It is shown that these additives lead to more than two-fold increase of the analytical signals from As, Se, and Те. The study of their effect on the formation of oxide ions of the main alloying components revealed the suppression of the formation of interfering polyatomic ions of chromium and titanium, the signals of which superimposed on the signal from 82Se. Harmful impurities in a complex alloyed sample of nickel alloy were determined using alcohol additives and other methods of suppressing spectral interferences. It is shown that determination of less than 2 pg/g of selenium necessitates the addition of 2 vol. % of ethyl alcohol. The correctness of the obtained results was confirmed by a comparative analysis of data obtained for the same sample by high resolution mass spectrometry with a glow discharge.

Heat-resistant materials used, for example, in aircraft parts, are exposed to high temperatures and are heated under the impact of variable external forces. At a certain point in time, the material that first experienced a small deformation ceases to be simply elastic and graduates into a viscoelastic state. Microyield thus developed in the material, subsequently leads to the creep. We present the results of studying the microyield in a heat-resistant polycrystalline alloy VZhl71 of the Ni - Co - Cr system. A high-temperature background of the internal friction was studied by mechanical spectroscopy. It is shown that the transition of the alloy from an elastic to a viscoelastic state proceeds in two stages and is accompanied by microyield resulted from the dislocation movement. The first and second activation energies of the high-temperatureinternal friction background are determined for the state of the material under consideration. An expression for calculating the transition temperature is derived. The results obtained can be used in the study of the states of heat-resistant, high-temperature and structured materials, as well as amorphous metals and alloys.

Modern electroplating usually suggests using electrolytes with special additives in the form of surface-active substances (surfactants). This is especially important for nickel plating electrolytes because of pitting, porosity, and low adhesion strength often accompanying the deposition of coatings is those electrolytes. We present the results of studying surface phenomena in nickel plating electrolytes using a K-100 KRUSS processor tensiometer. The Wilhelmy plate method was used to determine the surface tension of the standard Watts electrolyte and nickel-plating electrolytes added with surfactants, i.e., brightening (saccharin) and anti-pitting (RADO-11) additives. Surface phenomena at the electrolyte-solid interface have been analyzed using the OWRK model. The free energy of the solid surface (steel sample) has been estimated using the contact angle of the sample in test liquids (distilled water, re-hexane). It is shown that the anti-pitting additive RADO-11 is more effective compared to saccharin in increasing the wettability of steel samples and the adhesion strength at the electrolyte-solid interface. The results obtained can be used for nickel plating of plastics and polymer composite materials.

The paper presents the results of studying the dependence of the hardness of WC - Co alloy with a Co content of 10 wt.% on the character of the size distribution of WC grains. An equivalent diameter of the circle with an area matching the cross-section area of the grain was chosen as a grain size of the carbide phase. The WC grain sizes were averaged over their number, area and volume. It is shown that for the alloys with a narrow WC grain size distribution the hardness of the alloys as function of the average grain size follows the Hall - Petch relation. As for a wide distribution, a deviation from this function is observed. It is shown that the use of the area-averaged WC grain size enables description of the hardness as a function of the grain size via a unified Hall - Petch equation, regardless of the nature of the grain size distribution. In this case, the average scatter of hardness values around the trend line does not exceed 12 HV. The use of the volume-averaged grain size in description of the hardness dependence results in practice in a large scatter from the regression line, which is attributed to the error in determination of the content of coarse and very coarse grains, when one needs to measure significantly larger number of grains, as compared to averaging over the area. The results obtained may be used in analysis of single-phase and two-phase materials with grain size distributions with a varying width.

The mechanical testing performed to determine shear characteristics of advanced carbon fiber-reinforced plastics (CFRP) can involve significant problems. First of all, this is due to the difficulties in providing uniform distribution of shear stresses in the working area of the specimens, particularly in determining the strength characteristics of advanced polymer composite materials based on high-modulus or highstrength carbon fibers with the ±45° layup, where the material properties depend not only on the matrix but also on the fiber properties, unlike unidirectional composites. In addition, one can mention a large number of shear test methods and related standards of in-plane shear testing. At the same time, the results of the tests performed according to various standards generally do not comply with each other. In this study the analysis of CFRP shear characteristics obtained from various test methods was performed. The calculated and experimental data of stress-strain distribution for various specimen types were obtained. The experimental results of determining the strength and elastic characteristics of CFRP in the in-plane shear were obtained during the testing of 125 flat specimens made of four brands of CFRP reinforced with the ±45° plies. None of the standard methods discussed in this study was found to provide uniform distribution of shear stresses in the working area of the test specimen. The strength values closest to the predicted ones were obtained from the specimens made according to ASTM D7078 (GOST R 57207) based on the method of V-notch plate distortion. At the same time, the method of plate distortion in the four-bar linkage (GOST 24778, ASTM D2719) and the losipescu method (ASTM D5379, GOST R 56799) cannot definitely be used to reliably determine the shear strength characteristics of advanced CFRP reinforced with the ±45° plies.

The present article dedicated to influence of oxygen affected zone of VT41 heat-resistant titanium alloy's samples. The samples were made of 023 mm rods and 1 mm thick sheets and processed by short term heat treatment at 300 - 900°C in atmosphere furnace. Mechanical properties of samples were measured at room temperature by straining (rods) and bending (sheets) Surface of fractured samples were studied by means of ТЕМ. The results of the present work gave an opportunity to match the temper colors of the samples with the temperature of heat-treatment, mechanical properties and the depth of fragile oxygen affected zone. The dependencies of relative strain and reduction area versus heat-treatment temperatures were determined. It was defined that a critical changing of plasticity's characteristics appears at heattreatment temperature above 500°C. The appearance of bright temper colors leads to enlarging of dispersion of ultimate stress and critical bending angle. When temperature of annealing goes up to 800°C the bending angle of sheet-samples decrease significantly at room temperature. As accurate measuring of the depth of oxygen affected zone and thickness of Ti02 layer by means of optical metallography and fractography at low temperatures is seriously complicated than one could qualify a depth of oxygen affected zone on the spot by determining an annealing colors. The appearance of bright yellow annealing colors with metal shining didn't bring any critical changes of mechanical properties.

Improving research efficiency of mechanical stresses in metals can be achieved by studying and taking into account the fields of the trajectories of the main stresses (isostats), which qualitatively characterize the stress state. The purpose of the work was to determine the possibility of detecting the isostates in a St3 steel sample, following its plastic deformation. The methodology is based on the magnetoelastic method, manifested by the dependence of magnetic permeability of ferromagnetic materials upon mechanical stresses, acting in them. The method is implemented using the IMN-4M monophase magnetoelastic meter of mechanical stress: the base of the device gage is 5 mm, the angle meter error is ±2°. The sample is a plate with dimensions of 150 x 150 x 4 mm. Coordinate grids with 10 x 10 mm cells were applied to its front and back surfaces. Using the IMN-4M device, we measured the values of tilt angles for tangents to principal stress trajectories in all nodes, then we created isostates by consecutive adjustment of the direction and radius of curvature for a raised curve. The plastic deformation of a plate was performed by shooting small lead pellets with kinetic energy of 1916 J. The maximum plate curvature in the impact zone of main charge equaled 7 mm. After a shot, the measurements were repeated in the same nodes of coordinate grids, and the isostates were plotted again. The experiment has shown that: the magnetoelastic method makes it possible to detect the isostates even after plastic deformation; the trajectories are present both on front and back surfaces of the deformed plate; isotropic points and parallel isostates are available in fields, formed by the shot. Izotropic zones were formed on front and back surfaces, in which isostates can not be plotted due to random orientation of tangents. The "disturbances" of fields with disruption of regular trajectory flows were detected. The results of the work may be useful for researchers and technical engineers, engaged in the study of elastic and plastic deformations.